This is exactly what should happen. By dividing your Prob_1 outcome variable by $100$, you change the units (such as going between centimeters and meters).
When you do divide by $100$, you get that the error is $0.06002\space m^2$. When you do not divide by that $100$, you get that the error is $600.2\space cm^2$.
$$0.06002\space m^2 = 600.2\space cm^2$$
You might not be working in meters and centimeters, but these error values all have units, and you are getting the same answer whether you divide by $100$ or not, just in different units.